SQL Introduction

About SQL

SQL stands for Structured Query Language.

SQL is a language that enables you to work with a database. Using SQL, you can insert records, update records, and delete records. You can also create new database objects such as databases and tables. And you can drop (delete) them.

Although SQL is an ANSI (American National Standards Institute) standard, there are many different versions of SQL. Different database vendors have their own variations of the language.

Having said this, to be in compliance with the ANSI standard, they need to at least support the major commands such as DELETE, INSERT, UPDATE, WHERE etc. Also, you will find that many vendors have their own extensions to the language — features that are only supported in their database system.

Furthermore, transact-SQL is an extension to the ANSI standard and provides extra functionality.

Using SQL

To run the SQL queries in this tutorial, you will need a database management system such as MySQL, Oracle, Microsoft Access, SQL Server, etc.

Although SQL can be quite involved, you can achieve a lot with a handful of SQL statements. When using SQL on a website, you will often find yourself either selecting a record, inserting a record, updating a record, or deleting a record. Fortunately, SQL has commands for performing each of these actions.